1. Field of the Invention
The present invention relates to a clean combustion process and apparatus and, more especially, to such process/apparatus for the burning of heavy fuels.
By the term "heavy fuels", there is particularly intended:
(i) a fuel resulting from distillation of a crude oil, such as a fuel oil 4 to 6 in accordance with the ASTM standard (Burner Fuel Specification D 396; Cf. Perry and Chilton, Chemical Engineers Handbook, 5th edition, Section 9.9), or the crude oil itself;
(ii) or an emulsion;
(iii) or a partially or completely combustible suspension of a solid in a liquid or a gas.
By the expression "clean combustion," there is intended combustion without ultimate emission of polluting carbon-bearing particles.
2. Description of the Prior Art
It is known to this art that the emission of carbonaceous pollutants is a major disadvantage to the use of heavy fuels. Such phenomenon is manifest in the fact that solid residues are found to be formed and are included in any ash produced.
To date, however, no satisfactory solution to such problem has been found.
Now, in abandoned application, Ser. No. 916,477, filed June 19, 1978 and assigned to the assignee hereof, a process is featured for the intimate contacting of plural, physically disparate phases, wherein at least one phase is used to establish an axial helically spinning flowstream which is axially symmetrical and at least one other phase is introduced along the axis of symmetry of the axially helically spinning flowstream, into the region which is in condition of relative reduced pressure of said helical flow, with the momentum of the units of volume of the axial helical flow with respect to that of the units of volume of the axial phase introduced therein being such that the helical flow causes the rectilinear axial phase to be disintegrated, dispersed and entrained in the helical flow and optionally treated thereby.
In U.S. Pat. No. 4,124,353 assigned to the assignee hereof, process/apparatus is described for generating hot gases, by effecting combustion in a reaction zone which is in a state of relative reduced pressure within an axially symmetrical helical flowstream.
Consideration has also been given to supplying the apparatus in accordance with the aforementioned abandoned application, with a hot gas produced in accordance with the process of the aforesaid '353 patent.
However, serious technological problems were thus encountered, in particular when operating in high temperature ranges.
Next evolved the process/apparatus featured in U.S. Pat. Nos. 4,257,339 and 4,350,101, entailing effecting in situ generation of the hot gases in a first reaction zone by causing said gases to assume the configuration of an axially symmetrical helically spinning flowstream, and introducing the material to be treated into a region thereof which is in a state of relative reduced pressure, such as to avoid subjecting the sensitive or labile components of the apparatus to the prolonged action of the hot gases.
Such process/apparatus made it possible to use temperatures in excess of those temperatures deleterious to conventional steels, thus providing remarkable results as regards the size distribution of the drops produced and, consequently, the speed of vaporization of such drops.
However, it too is known that the combustion of heavy fuels poses especially unique problems due to a lack of homogeneity in the spraying thereof, which results notably in the formation of polluting black particles (soot, cenospheres, and the like). Cf. U.S. Pat. Nos. 4,263,234, 4,265,702 and 4,267,131.